Summary: IEEE INFOCOM 2001 1
Modeling the Branching Characteristics and
Efficiency Gains in Global Multicast Trees
Robert C. Chalmers, Kevin C. Almeroth
Abstract-- In this paper, we investigate two issues. First, what level of
efficiency gain does multicast offer over unicast? Second, how does the
shape of multicast trees impact multicast efficiency? We address the first
issue by developing a metric to measure multicast efficiency for a number
of real and synthetic datasets. We find that group sizes as small as 20 to 40
receivers offer a 60-70% reduction in the number of links traversed com-
pared to separately delivered unicast streams. Addressing the second issue,
we have found that almost all multicast trees have similar characteristics in
terms of key parameters such as depth, degree frequency and average de-
gree. A final contribution of our work is that we have taken multicast group
membership data and multicast path data and compiled datasets which can
be used to generate large, realistic multicast trees.
Keywords--Multicast, measurement, modeling, tree characteristics.
I. INTRODUCTION
ULTICAST provides a conceptual advantage for design-
ers developing applications with support for a large, dis-